Introduction:
Weather is a dominating factor in the Ubers metagame—that's a given. With forces such as Groudon and Kyogre controlling the match, and even Tyranitar's ability to set up Garchomp, Excadrill, and similar offensive threats, there's no denying that statement. It's hard to imagine what a metagame without weather would be like, and questions such as "Would people still run Thunder on Palkia?" or "Would Reshiram still be a major offensive threat without sun?" would be pulled out; however, in this tournament, we aim to explore how influential weather is in the metagame.

Weather:
You cannot use any Pokemon with a weather-inducing ability or any weather-inducing moves. This means you cannot use Groudon or Kyogre, and Ninetales with Drought, Politoed with Drizzle, Tyranitar with Sand Stream, Hippowdon with Sand Stream, Abomasnow with Snow Warning, etc. However, you may use a Pokemon that has another ability available (e.g. Ninetales with Flash Fire, Politoed with Damp).

Battles are to be played on Pokemon Showdown!, but if both players agree, battles can occur on Pokemon Online. However, Smogon's tiering rules apply no matter where the battle is held.